<!DOCTYPE html>
<html>
<body style="color: black; background: white">
  <div style="opacity: 0">Test 1</div>
  <div style="opacity: -1">Test 2</div>
  <div style="opacity: -0.5">Test 3</div>
  <div style="opacity: -6.7">Test 4</div>
  <div style="opacity: 1">Test 5</div>
  <div style="opacity: 1.5">Test 6</div>
  <div style="opacity: 2">Test 7</div>
  <div style="opacity: 7.3">Test 8</div>

  <div style="color: rgba(0, 0, 0, 0)">Test 9</div>
  <div style="color: rgba(0, 0, 0, -1)">Test 10</div>
  <div style="color: rgba(0, 0, 0, -0.5)">Test 11</div>
  <div style="color: rgba(0, 0, 0, -6.7)">Test 12</div>

  <div style="color: rgba(0, 0, 0, 1)">Test 13</div>
  <div style="color: rgba(0, 0, 0, 1.5)">Test 14</div>
  <div style="color: rgba(0, 0, 0, 2)">Test 15</div>
  <div style="color: rgba(0, 0, 0, 7.3)">Test 16</div>
</body>
</html>
